<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script>
    var func=function(fx){
        return fx();
    };
    
    function callback(){
        return 10;
    }
    var result= func(callback);
    console.log("result : "+result);
    
    var result = func(function(){
        return "nice";
    });
    console.log("result : "+result);
    
    var result = func(function(){
        return function(){
            console.log("test...00");
        };
    });
    console.log("result : "+result);
    console.log("result : "+result());
</script>
</head>
<body>

</body>
</html>